1. Field of the Invention
This invention relates generally to an improvement in a cylinder block for an internal combustion engine, and more particularly to a cylinder block construction effective to reduce the vibration-noise radiated therefrom to achieve total engine noise reduction.
2. Description of the Prior Art
In connection with an internal combustion engine for use, for example, in an automotive vehicle, it is well known that a cylinder block to which a cylinder head and an oil pan are secured, has an upper section having therein a plurality of engine cylinder bores, and a lower section or skirt section which is generally bulged outwardly to form thereinside a crankcase for an engine crankshaft. However, such an engine has the problem that the cylinder block thereof vibrates due to fuel combustion pressure and reciprocal engine piston movement. Additionally, this cylinder block vibration causes the skirt section to vibrate, thus radiating a considerable high-level noise from the surface of the skirt section. Such vibrations of the cylinder block are considered to result from a shortage in torsional and flexural rigidities of the cylinder block.